Method of forming a photographic washout coupler (BARC) using a strong base

Abstract

A method of forming a photographic coupler (A) having the formula: (SOL).sub.x --COUP--(R.sup.1).sub.y --(R.sup.2).sub.z --BLEACH comprising: (a) providing a coupler (B) having a coupling-off group represented by the formula: ##STR1## (b) reacting said coupling-off group of coupler (B) with phosgene to provide a chloroformate coupling-off group of coupler (B) (c) reacting said chloroformate coupling-off group of coupler (B) in the presence of a strong base selected from the group consisting of triethylamine, N,N-diisopropylethylamine, and tetramethylguanine with: R.sup.14 --R.sup.13 --SH to provide the R 2 group and the BLEACH group of the coupler (A).

What is claimed is: 
     
       1. A method of forming a photographic coupler selected from the group consisting of ##STR25## wherein: Ballast is a photographic ballast; the method comprising reacting phosgene with a compound having the formula ##STR26## to form a chloroformate having the structure ##STR27## and reacting the chloroformate, in the presence of a strong base selected from the group consisting of triethylamine, N,N-diisopropylethylamine, and tetramethylguanidine, with a thiol selected from the group consisting of ##STR28## to form the photographic coupler.   
     
     
       2. The method according to claim 1, wherein the base is selected from triethylamine and N,N-diisopropylethylamine. 
     
     
       3. The method according to claim 1, wherein the photographic coupler is ##STR29## 
     
     
       4. The method according to claim 1, wherein the photographic ballast is NHSO 2  C 16  H 33  -n.